Every serious debate about papal infallibility eventually arrives at the same name: Honorius. He is not the most dramatic pope in history—no Borgia scandals, no Avignon captivity, no spectacular clash with emperors. He was, by all contemporary accounts, a man of personal holiness, administrative vigor, and genuine pastoral concern. He built churches, sent missionaries to the Anglo-Saxons, and governed the patrimony of St. Peter competently for thirteen years. And yet he is the single most devastating historical argument that opponents of papal infallibility have ever deployed—because an ecumenical council condemned him as a heretic, and a subsequent pope confirmed the condemnation.

For Orthodox Christians, Honorius is Exhibit A: proof that the Bishop of Rome was never considered infallible by the early Church. For Protestants, he is the silver bullet against Roman claims. For many Catholics, he is a source of quiet embarrassment, papered over with reassurances that “he wasn’t speaking ex cathedra”—which is true, but which is not, by itself, a serious enough answer. The case demands more.

I. The Background: Monophysitism, Monoenergism, and the Imperial Search for Unity

The Monothelite heresy did not arise from nowhere. It was the final iteration of a long chain of Christological controversies stretching back to Chalcedon (451). The Council of Chalcedon had defined that Christ possesses two complete natures, divine and human, “without confusion, without change, without division, without separation.” Vast populations in Egypt, Syria, and Armenia rejected this formula, insisting instead on the Monophysite position that Christ’s two natures were merged into one after the Incarnation. The resulting schism tore the Eastern Empire apart for over two centuries.

Every Byzantine emperor from Zeno (474–491) onward attempted some formula of reunion. The latest effort was Monoenergism—the proposal, championed by Patriarch Sergius of Constantinople and Patriarch Cyrus of Alexandria, that Christ possesses two natures but only “one theandric operation” (mia theandrikē energeia). In 633, Cyrus used this formula to reunite a significant number of Egyptian Monophysites with the Chalcedonian Church. Emperor Heraclius was delighted. Sergius was the architect of the policy.

There was one problem: Sophronius, a monk of enormous theological acumen who had already spent decades fighting Monophysitism across the East. In 634, Sophronius became Patriarch of Jerusalem. Within weeks of his enthronement he assembled a synod of his bishops, condemned Monoenergism, and issued his celebrated synodical letter—sent to the Pope and to all the Eastern patriarchs—demonstrating that two complete natures necessarily imply two operations and two wills. Sophronius had grasped what Sergius was trying to obscure: the “one operation” formula was a concealed denial of Christ’s complete humanity.

II. The Letters: What Honorius Actually Wrote

Alarmed by Sophronius’s opposition, Sergius wrote to Pope Honorius in 634, presenting the controversy in the most irenic possible terms. He framed the question of “one or two operations” as a terminological dispute best resolved by enforcing silence on both sides. He then implied—with calculated sleight of hand—that admitting two wills in Christ would mean admitting two opposing wills, as though the human will of Christ could resist the divine will.

Honorius fell into the trap. In his first letter to Sergius, he endorsed the policy of silence, dismissing the controversy as a matter for “grammarians.” Then came the sentence that would haunt the papacy for fourteen centuries:

Read in isolation, the sentence is Monothelite. It affirms “one will” in Christ—the very formula that Constantinople III would condemn as heretical forty-five years later. But what did Honorius mean?

The context makes his intention clearer, though it does not exonerate his formulation. Immediately after the fateful sentence, Honorius explains why he confesses one will: because Christ did not assume a natura vitiata—a corrupted nature with its rebellious “law of the members”—but rather the uncorrupted human nature as it existed before the Fall. In other words, Honorius was not denying that Christ has a human will; he was denying that Christ has two opposing wills, one of which rebels against God. His point was about the moral harmony of Christ’s willing, not about the metaphysical number of His faculties.

This reading was defended by Honorius’s own secretary, the scribe Abbot John Symponus, who later testified that the text referred to the human will alone: “When we spoke of a single will in the Lord, we did not have in view His double nature, divine and human, but His humanity only.” It was defended by Honorius’s successor Pope John IV (640–642), who wrote to Emperor Constantine III explaining that Honorius had spoken “only of the human and not also of the divine nature.” And it was defended by the greatest theologian of the seventh century, St. Maximus the Confessor, who in his Opusculum 20 (c. 641) argued vigorously that Honorius had never denied the existence of a natural human will in Christ.

But there is a darker side to the evidence. In his second letter to Sergius (only fragments survive), Honorius again rejected as “inexpedient” the formula “two operations”—the very formula that Sophronius and Maximus and the entire orthodox tradition would vindicate as correct. And Honorius did not merely err in words; he actively endorsed Sergius’s policy of silence—forbidding the orthodox terminology as well as the heretical one. This policy of silence was not neutral: it handed the Monothelites a devastating weapon, because Honorius’s letter was subsequently cited as the papal foundation for the Ecthesis—the imperial decree of 638, drafted by Sergius, that imposed Monothelitism as the law of the Church and Empire.

III. The Aftermath: How Rome Corrected Course

Honorius died on 12 October 638, the same year the Ecthesis was published. His successors did not wait forty years for a council to correct his error. The record of Rome’s self-correction is unambiguous and powerful—and is itself significant evidence for, not against, the reliability of the Roman See:

Pope Severinus (640) condemned the Ecthesis outright before even being consecrated. Pope John IV (640–642) rejected Monothelitism and defended Honorius’s intention (while implicitly abandoning his formula). Pope Theodore (642–649) issued condemnations and anathemas against the Monothelite patriarchs. Pope Martin I (649–653) held the Lateran Council of 649, whose acts—sent throughout East and West—anathematized the Ecthesis and the Typos, condemned Sergius, Cyrus, Pyrrhus, and Paul by name, and affirmed two wills and two operations in Christ. Crucially, Martin’s Lateran Council made no mention of Honorius, treating the problem as having originated in Constantinople, not Rome.

For his defiance of the emperor, Martin I was arrested in Rome in 653, dragged to Constantinople, subjected to a humiliating public trial, and exiled to Crimea, where he died in 655—the last pope to be venerated as a martyr. St. Maximus the Confessor, Martin’s theological ally, suffered even worse: his tongue was cut out and his right hand amputated. He died in exile in 662. Both are honored as saints by the Catholic and Orthodox Churches alike.

IV. The Council: What Constantinople III Actually Said

The Third Council of Constantinople (the Sixth Ecumenical Council) convened on 7 November 680, convoked by Emperor Constantine IV with the full participation of papal legates sent by Pope St. Agatho (678–681). Agatho had sent a dogmatic letter—sometimes compared to Leo I’s Tome—affirming the orthodox doctrine of two wills and two operations in Christ. The Council received Agatho’s letter with the acclaim that had greeted Leo’s Tome at Chalcedon: “Peter has spoken through Agatho!”

The Council then proceeded to examine the evidence and condemn the authors and abettors of the Monothelite heresy. In its thirteenth session, on 28 March 681, it pronounced its anathema:

The language is blunt. Honorius is grouped with the Monothelite patriarchs. He is said to have “followed” Sergius “in all things” and “confirmed his impious doctrines.” This is the strongest version of the condemnation, and no Catholic who takes history seriously should pretend it doesn’t exist.

V. Leo II: The Confirmation That Changes Everything

But conciliar decrees have no binding force for Catholics until confirmed by the Pope. Agatho died on 10 January 681, before the Council concluded. His successor, Pope St. Leo II (682–683), received the Council’s acts and confirmed them—but with a crucial recharacterization of Honorius’s fault. Leo’s letter to Emperor Constantine IV reads:

Notice the distinction. The Council said Honorius “followed Sergius in all things” and “confirmed his impious doctrines.” Leo II says Honorius “did not attempt to sanctify” the Apostolic Church with apostolic tradition but “permitted its purity to be polluted.” Writing to the Spanish bishops, Leo was even more precise: Honorius was condemned for “not at once extinguishing the flames of heresy, but rather fanning them by his negligence.”

The difference is not cosmetic. Leo II shifts the charge from teaching heresy to permitting heresy through negligence. The Council charged Honorius with actively confirming impious doctrines; Leo II charged him with failing to defend the faith. Since the Council’s authority depends on papal confirmation, and since Leo II confirmed the condemnation in the sense of negligence rather than formal heresy, the Catholic position holds that the binding force of the anathema is defined by Leo II’s qualifying language.

VI. The Orthodox Argument: Engaging the Strongest Version

Orthodox and Protestant apologists are not wrong to press this case. The strongest version of their argument runs as follows:

VII. Maximus the Confessor: The Orthodox Saint Who Defended the Pope

There is a deeply ironic dimension to the Honorius case that is rarely noted: the greatest champion of Orthodoxy in the Monothelite crisis was also the most vigorous defender of both Honorius’s personal orthodoxy and of Roman primacy.

St. Maximus the Confessor (580–662), venerated as a saint and Doctor of the Church in both Catholic and Orthodox traditions, argued in his Opusculum 20 (c. 641) that Honorius had never denied the existence of a natural human will in Christ. In his Disputation with Pyrrhus (645), when the former Patriarch of Constantinople cited Honorius as evidence for Monothelitism, Maximus defended the Pope point by point. He went further: Maximus reported that Honorius’s secretary, Abbot John Symponus, who had physically written the letter, testified that the “one will” phrase had been distorted in translation from Latin to Greek—that Honorius never used a numerical term in the original dictation.

More broadly, Maximus’s ecclesiology was profoundly Roman. His Letter A to Thalassios (c. 640) and Opusculum 12 (c. 645) contain among the most effusive statements of Roman doctrinal preeminence in the entire patristic corpus. This is the man whom both Catholic and Orthodox tradition honors as the theological hero of the Monothelite crisis—and he defended Honorius and insisted on the unique doctrinal authority of Rome.

VIII. Honorius at Vatican I: The Known Quantity

The case of Honorius was not a skeleton in the closet that the Fathers of Vatican I hoped nobody would notice. It was the central historical objection to defining papal infallibility. Döllinger made it the centerpiece of his anti-infallibilist polemic in Der Papst und das Konzil (1869). Bishop Hefele, the great historian of the councils, pressed the case in detail on the floor of the Council. It was debated, argued, and wrestled with.

The Council Fathers’s response was not to deny the facts but to define infallibility in a way that explicitly accounted for them. As Chapman wrote: “It is absurd to regard the letter of Honorius to Sergius as a definition ex cathedra. Honorius addresses Sergius alone, and it is by no means evident that he intended his letter to be published as a decree.” The four cumulative conditions of Pastor Aeternus—that the pope speak as universal pastor, in virtue of his apostolic authority, defining a doctrine of faith or morals, to be held by the whole Church—were deliberately calibrated to exclude cases like Honorius’s correspondence with Sergius.

Chapman’s honesty is bracing—and his point is precise. Honorius was a heretic in words. His formula was objectively Monothelite. But he was not a heretic in intention, and he was not exercising the charism of infallibility. The distinction between what a pope says in correspondence and what a pope defines ex cathedra is not a post-hoc rationalization; it is the very distinction that the Council Fathers of Vatican I forged with the Honorius case in full view.

IX. What This Case Does and Does Not Prove

Intellectual honesty requires us to state clearly what the Honorius case proves and what it does not.

It proves that a pope can err—gravely, scandalously—when not exercising the extraordinary magisterium. It proves that a pope can use heretical language without intending heresy. It proves that a pope can adopt a catastrophically bad disciplinary policy (enforced silence) that hands ammunition to heretics. It proves that an ecumenical council can condemn a pope for these failures. It proves that the seventh-century Church did not believe in the kind of unlimited, quasi-oracular papal authority that nineteenth-century maximalists like Veuillot and Ward wanted to define. None of this is news. The Church has always known it.

It does not prove that a pope has ever erred when exercising the ex cathedra teaching office as defined by Pastor Aeternus. Honorius’s letters to Sergius fail every one of the four conditions of the definition. They are not addressed to the universal Church. They do not invoke apostolic authority to define doctrine. They do not propose a binding formulation of faith. They do not intend to settle a question definitively. They are, as Chapman rightly noted, the correspondence of a pope who did not grasp the theological implications of a controversy he treated as a matter of grammar.

X. Modern Orthodox Scholarship on Honorius

Modern Orthodox theologians have engaged the Honorius case with varying degrees of sophistication. John Meyendorff, in Imperial Unity and Christian Division (1989), argued that Honorius “actually coined a heretical formula” and that Catholic attempts to apply the ex cathedra distinction are “anachronistic”—since no such concept existed in the seventh century. Kallistos Ware used Honorius as evidence that the early Church did not consider the Bishop of Rome infallible. Both are cited extensively in Protestant and Orthodox polemics.

The Catholic response, as noted above, is that dogmatic precision develops historically. The ex cathedra distinction was not articulated in the seventh century, just as the two-natures language of Chalcedon was not articulated in the first century. That does not make it anachronistic; it makes it a development—the same kind of development that Newman described in his Essay on the Development of Christian Doctrine (1845). The question is not whether seventh-century Christians used the vocabulary of 1870, but whether the evidence of their practice and belief is consistent with the distinction 1870 would later articulate. The fact that Constantinople III itself acclaimed Agatho’s letter as the voice of Peter—while condemning Honorius for failing to exercise the same teaching authority—suggests that the practice, if not the terminology, was already present.

XI. The Broader Lesson: Fallibility, Infallibility, and the Roman See

The Honorius case is, paradoxically, a stronger argument for the reliability of the Roman See than against it. Consider the full picture: one pope erred in a letter. His five successors corrected him—one at the cost of his life. The Roman See’s institutional record during the Monothelite crisis is one of heroic fidelity to Chalcedonian orthodoxy, not of complicity with heresy. Popes Severinus, John IV, Theodore, Martin I, Eugene I, Vitalian, Adeodatus II, Donus, and Agatho all maintained the orthodox faith against imperial pressure, Constantinopolitan intrigue, and physical violence.

As Edward Feser has noted, the relevant question is not “Has a pope ever erred?” (the answer is yes, and the Church has always known it) but “Has a pope ever erred when exercising the specific charism defined by Vatican I?” The answer, after two millennia, remains no. Honorius is the hardest case—and if the hardest case does not breach the definition, the definition stands.